Automated clinical chemistry analyzer systems that analyze body fluid samples such as treated whole blood, blood serum, blood plasma and urine have been developed with the capability of performing multiple analytical tasks in assembly line fashion as detailed in U.S. Pat. Nos. 5,268,147 and 5,399,497, owned by the assignee hereof. Certain of such systems carry out multiple high speed analytical tests automatically by providing a stream of sample test packets, separated by a gas such as air, that flow through the system in a small diameter fluid conduit. As the stream of sample test packets flows through the system, a number of different tests and measurements are performed.
Automation of analytical testing has many advantages over manual laboratory testing procedures. Improved process control leads to improvements in accuracy and repeatability of the test results. In addition, automated testing can provide results much more rapidly and more cost effectively than manual testing.
Typically, prior to being inserted into the flowing stream for testing, a sample is mixed with one or more prepared reagents or diluents. Diluents such as an aqueous salt solution are used to reduce the analyte concentration of a sample to bring it within the range that can be measured by the system. Reagents are used to generate the chemical reactions necessary for certain testing methods, such as vitamin B12 and folate (folic acid).
Some automated clinical chemistry analyzer systems include a number of different modular subsystems. These may include a pretreatment module in which the sample mixtures described above are prepared and in which certain chemical reactions are generated, and various analytical modules in which the actual testing and analysis of the sample mixtures is performed. Typically, a mechanism, such as a robotic arm, is provided for transporting the sample mixtures between the modules.